Inorganic anions, HPLC

CE has been used for the analysis of anionic surfactants [946,947] and can be considered as complementary to HPLC for the analysis of cationic surfactants with advantages of minimal solvent consumption, higher efficiency, easy cleaning and inexpensive replacement of columns and the ability of fast method development by changing the electrolyte composition. Also the separation of polystyrene sulfonates with polymeric additives by CE has been reported [948]. Moreover, CE has also been used for the analysis of polymeric water treatment additives, such as acrylic acid copolymer flocculants, phosphonates, low-MW acids and inorganic anions. The technique provides for analyst time-savings and has lower detection limits and improved quantification for determination of anionic polymers, compared to HPLC. 

The above results show that conventional HPLC can be used with UV detection for the determination of inorganic anions, namely 103, N02-, Br-, N03 and I" with a cationic micellar mobile phase. One of the attractive features of this procedure is the ability to control retention by control of the concentration of aqueous micellar hexadecyltrimethylammonium chloride rather than by the use of organic modifiers. 

The molecular characterization of methylarsonic acid, phenylarsonic acid and the inorganic anion, arsenate, found in a methanol extract of a Green River Formation Oil shale sample was accomplished by HPLC-GFAA analysis In addition, derivatization of the acids, HPLC purified, by reaction with 3-methylcatechol to form the five coordinate organoarsenic catecholates as well as reaction, via trimethylsilylation, of the ammonium salt of arsenate to form tristrimethylsilylarsenate was followed by GC-EIMS analysis to provide unequivocal evidence for the presence of these organometallic and inorganic compounds of arsenic as natural products in oil shale ... 

The retention model developed by Eon and Guiochon [7,8] to describe the adsorption effects at both gas-liquid and liquid-solid interfaces, which was later modified by Mdckel et al. [6] to account for the retention at chemically bonded reversed-phase materials in HPLC, is not applicable to ion chromatography. But if the dependence of the capacity factors of various inorganic anions on the column temperature is studied, certain parallels with HPLC are observed. The linear dependences shown in Fig. 3-2 are obtained for the ions bromide and nitrate when the In k values are plotted versus the reciprocal temperature (van t Hoff plot). However, in the case of fluoride, chloride, nitrite, orthophosphate, and sulfate, the k values were found to be constant within experimental error limits in the temperature range investigated. Upon linear regression of the values in Table 3-1, the following relations are derived for bromide and nitrate ... 

The procedure developed by Bradfield and Cooke is an example of an extraction procedure used for the 1C determination of anions in plant materials.Here, the extraction of anions from 100 mg of fresh plant material (nondried rape) was carried out with 5 ml of deionized water at 70°C for 30 min, followed by filtration through Whatman No.541 filter paper, prior to analysis using ion-pair RP-HPLC. Slightly modified procedures followed by micro-filtration have been used for the determination of inorganic anions, including phosphate, in dried potatoes, coffee beans and tea, tomato, pumpkin, turnip, and lettuce leaves, and spinach. A more unusual extraction solution of... 

Experiment 31. Determination of the amino acid composition of a peptide using pre-column derivatisation with o-phthalaldehyde and reverse phase HPLC and fluorescence detection Experiment 32. Analysis of inorganic anions in aqueous samples... 

Ion chromatography (IC) is a low- to moderate-pressure liquid chromatographic (LC) technique and should be clearly distinguished from that of high-pressure LC (HPLC). IC as a determinative technique has been developed to separate both cations and anions. The instrument available to the student utilizes anion-exchange IC with suppressed conductivity detection. This technique can separate the common inorganic anions, fluoride,... 

F.G.P. Mullins, HPLC of Organic and Inorganic Anions Use of Micellar Mobile Phases, ACSSymp. Ser., 342 115 (1987). 

F.G.P. Mullins and G.F. Kirkbright, Determination of Inorganic Anions by HPLC using a Micellar Mobile Phase, Analyst, 109 1217 (1984). 

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